Simplified basting stitch mechanism

ABSTRACT

A basting stitch mechanism in a zigzag sewing machine utilizing a latch carried by a needle bar selectively to connect and disconnect the actuating mechanism of the sewing machine to drive the needle bar in endwise reciprocation. To impart zigzag motion to the needle, the needle bar is supported for endwise reciprocation in a gate journaled for lateral oscillation about an axis inclined to the axis of needle bar reciprocation. This arrangement amplifies the relative motion between the needle bar and the gate so that it may be utilized during an extreme lateral excursion of the gate to trip the latch mechanism carried by the needle bar by means of an abutment member mounted on the gate. By mounting the gate in a supporting bracket which is attachable to the sewing machine, the gate, needle bar and basting stitch mechanism may be subassembled and partially adjusted prior to installation into the sewing machine with only simple adjustments required after installation.

[ jam, 1, i974 Primary Eraminer-Werner H. Schroeder Attorney-Marshall J. Breen et al.

[57] ABSTRACT A basting stitch mechanism in a zigzag sewing machine utilizing a latch carried by a needle bar selectively to connect and disconnect the actuating mechanism of the sewing machine to drive the needle bar in endwise reciprocation. To impart zigzag motion to the needle, the needle bar is supported for endwise reciprocation in a gate journaled for lateral oscillation about an axis inclined to the axis of needle bar reciprocation. This arrangement amplifies the relative motion between the needle bar and the gate so that it may be utilized during an extreme lateral excursion of the gate to trip the latch mechanism carried by the needle bar by means of an abutment member mounted on the gate. By mounting the gate in a supporting bracket which is attachable to the sewing machine, the gate, needle bar and basting stitch mechanism may be subassembled and partially adjusted prior to installation into the sewing machine with only simple adjustments required after installation.

5 Claims, 12 Drawing Figures 112/158R D05b 3/02 112/79, 163, 167, 112/158 R, 158 A, 221

Salvatore A. DOrio, Staten Island NY.

The Singer Company, New York, NY.

Dec. 29, 1972 References Cited UNITED STATES PATENTS SIIMPLHIFHED lBASTlNG STITCH-ll MECHANISM Inventors: Kenneth D. Adams, Madison, NJ,-

Assignee:

Filed:

Appl. No.: 319,426

Field of Search......................

ijlliifi Adams et al.

I SIMPLIFIED lllAS'llllhlG STITCH MECHANISM BACKGROUND OF THE INVENTION This invention relates to a basting stitch mechanism in a zigzag sewing machine wherein the needle bar is driven in endwise reciprocation through a latch mechanism affixed to the needle bar.

In prior art sewing machines, lateral oscillation of the needle bar to produce zigzag stitching is accomplished by mounting the needle bar in a gate mechanism journaled on the sewing machine frame and caused to undergo lateral oscillation by linkage which is responsive to a cam mounted elsewhere within the sewing machine frame. With this arrangement the lateral oscillations of the needle bar can be programmed by providing suitable cam surfaces to produce ornamental stitching of varying degrees of width or bight ranging from straight stitch to the greatest width at which the machine is capable of producing a stitch, sometimes called maximum bight.

The U. S. Pat. No. 3,559,601, Feb. 2, 1971 to Tullman discloses such a prior art machine having, in addition, a basting stitch mechanism with a latch mecha nism affixed to the needle bar. This basting stitch mechanism operates to unlatch the needle bar from its driving mechanism when the gate is driven to an extreme excursion beyond the maximum bight of the sewing machine. In the patented construction, the extreme movement of the needle bar carried by the gate in the extreme excursion causes the latch, affixed to the nee dle bar, to strike a bracket, adjustably attached to the frame of the sewing machine, thereby unlatching the its driving mechanism. The latch is then trapped with the needle bar in an elevated position by a second bracket, also adjustably attached to the sewing machine frame.

The mounting of the brackets on the sewing machine frame in the above prior art machine required several adjustments to be made on the assembled machine to achieve a proper operating status. These adjustments are sensitive in nature and susceptible to rapid change due to wear and distortion of the brackets, one of which was also used to support the pressure regulating mechanism of the sewing machine pressure bar. Improper adjustment of the brackets accelerated the wear and distortion encountered during machine operation and contributed to noisy machine operation.

SUMMMARY OF THE INVENTION This invention overcomes the above difficulties by creating and utilizing relative motion between the gate supporting the needle bar and the needle bar to unlatch the latch mechanism mounted on the needle bar through an abutment member mounted on the gate itself. By utilizing a supporting bracket attachable to the sewing machine frame to support the gate for lateral oscillation, the gate, needle bar and basting stitch mechanism can be subassembled and initially adjusted externally of the machine, requiring only simple adjustments after attachment to the sewing machine frame. An extension spring is utilized to bias the needle bar is an upward direction, thereby obviating the need for a separate bracket mounted on the sewing machine frame to hold the needle bar in an elevated position when unlatched from the driving mechanism.

Thus, all brackets previously required to be adjustably attached to the sewing machine frame have been eliminated, that bracket or abutment member that is required being mounted on the gate itself. Further the abutment member serves the single purpose of unlatching the latch mechanism mounted on the needle bar.

DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention is shown in the drawings in which:

FIG. l is a vertical head end view partly in section of a sewing machine showing the arrangement of the gate axis of oscillation to the needle bar axis of reciprocation;

FIG. 2 is a front elevational view of the sewing head portion of a sewing machine shown in FIG. 1',

FIG. 3 is a top elevation of the cam mechanism utilized to drive the needle bar in the basting stitch mode;

FIG. 4 is a detached front elevation of the latch mechanism attached to the needle bar;

FIG. 5 is a perspective view of the upper half of the needle bar and gate showing the latch mechanism attached to needle bar engaged with the driving mechanism causing needle bar reciprocation;

FIG. 6 is a perspective view similar to FIG. 5 but with the latch mechanism shown in the disengaged position and the driving mechanism freely sliding on the needle bar;

FIGS. 7, 8 and 9 are views of the needle bar gate assembly, with the gate partially broken away, in the left needle position, right needle position and basting position respectively, and;

FIGS. 10, 11 and 12 are top sections taken through the gate and needle bar corresponding to FIGS. 5, 6 and 7, respectively.

Referring to FIG. 1, there is shown a sewing head II of a sewing machine held by an arm and a standard (not shown) in overhanging relation to a bed 12 which contains a throat plate 13 and a bed slide plate 14 Cover ing the front of the machine is a front cover 15. Attached to the sewing head l I by screws in is a supporting bracket 17 having an upper forwardly extending arm 18 and a lower forwardly extending arm l8 and a lower forwardly extending arm 19. A presser bar bushing 20 is held in the supporting bracket I7 by a screw 21. Journaled in the presser bar bushing 20 is a presser bar 22 to one end of which is affixed a presser foot 23 by a screw 24. The end of the presser bar 22 opposite that to which the presser foot 23 is affixed supports a collar 25 attached thereto by a screw 26. The collar 25 contains a tang 27 which projects through a cut out section (not shown) in the supporting bracket 17. A presser bar lifting lever 28 journaled on a shoulder screw (not shown) threaded into the supporting bracket 17, abuts the tang 27 to effect lifting of the presser foot 23 when desired. Not shown is the pressure regulating system for the presser bar 22 which is mounted on a pressure regulating system mounting plate 30 whose outline is indicated in FIGS. I and 2 by dot'dash lines.

Journaled in the supporting upper forwardly extending arm extending arm 19 there is a gate having an upper rearwardly extending arm36 and a lower rearwardly extending arm 37. Into the upper rearwardly extending arm 36 of gate 35 is inserted an upper bearing 3% having both an internal bearing surface 3% and an outer spherical surface MI in coaxial relationship. The upper forwardly extending arm 18 of the supporting bracket bracket 17 within the 18 and lower forwardly 17 contains a socket bearing 42, having an enlarged central hole 41, in a bore 44. The axial position of the socket bearing 42 may be fixed by a screw 43 threaded through the front portion of the upper forwardly extending arm 18 to the bore 44. Into the lower rearwardly extending arm 37 of the gate 35 is inserted a lower bearing 45 having a socket bearing surface 46 and an internal bearing surface 47 spaced from each other. The spherical head of a pivot stud 48, contained in a bore 49 in the lower forwardly extending arm 19 of the supporting bracket 17, is received by the socket bearing sruface 46 of the lower bearing 45. Assembly of the gate 35 to the supporting frame 17 is facilitated by loosening screw 43 affixing socket bearing 42 in the arm 18 of the supporting bracket 17 and positioning the socket bearing out of the way, inserting the gate in the space thus provided, after which socket 42 may be seated against the outer spherical surface 40 of the upper bearing 38 and reclamped in position by tightening the screw 43.

Contained to reciprocate by the internal bearing surfaces 39 and 47 of upper bearing 38 and lower bearing 45 respectively within the enlarged central hole 41 of the socket bearing 42 and through an opening 60 in the lower forwardly extending arm 19 of the supporting bracket 17, is a needle bar 50 adapted to have fitted to one end thereof a needle 51. The needle reciprocates along a path indicated by the line 52 in FIG. 1 and cooperates with a loop taker (not shown) in the bed 12 of the sewing machine in the formation of lock stitches in the usual manner. Reciprocation of the needle bar 50 is effected in the usual manner by an arm shaft 53 located in the arm of the sewing machine having a crank 54 at one end thereof. The crank is provided with a stud 55 to which is connected a link 56, having a sliding and oscillating connection at its other end with a driving stud 57 (see FIG. 4). The driving stud 57 has a bifurcated portion 58 at one end which clasps both ends ofa collar 59 freely slidable on the needle bar 50.

A latch mechanism 61 is affixed to the needle bar 50 in its upper portion (see FIGS. 4, and 6). A rectangular collar 62 having a downwardly extending tang 63 which is received in the bifurcated portion 58 of the driving stud 57, contains a threaded hole which receives a screw 64 having an elongated head portion 65. The screw 64 extends through the threaded hole in the rectangular collar 62 and firmly attaches the collar to the needle bar 50. Located on the front side of the rectangular collar 62 and supported on an eccentric collar 69, held positioned to the rectangular collar by a screw 70, is latch lever 71. The latch lever 71 has a forwardly extending ear 72 spaced from the eccentric collar 69 and a rearwardly extending lug having a latch surface 73 located a sufficient distance from the eccentric collar to grip the lower edge of the bifurcated portion 58 of the driving stud 57 when the bifurcated portion is in intimate contact with the lower surface of the rectangular collar 62. Adjustments for proper clearance between the latch surface 73 and bifurcated portion 58 are provided for by rotation of the eccentric collar 69 on which latch lever 71 is supported and tightening of the screw 70 to hold the eccentric collar in the selected adjusted position.

Also supported by the eccentric collar 69 and biased on the rectangular collar 62 is a torsion spring 75. The torsion spring 75 biases the latch lever 71 in counterclockwise direction, as viewed in FIG. 4, thereby to engage the rearwardly extending latch surface 73 onto the bifurcated portion 58 of the driving stud 57. Opposite the screw 64 of the rectangular collar 62 is a post 77 extending from the collar, which post contains a peripheral groove 78 on its end. The peripheral groove 78 receives one end of a needle bar elevating spring 79, the other end of which is supported on a projection 80 of a lever 81 attached to the supporting bracket 17. The spring 79 serves to elevate the needle bar 50 whenever the latch surface 73 is disengaged from the bifurcated portion 58 of the driving link 57.

Attached by a screw 84 in a slot 83 fonned in the supporting bracket 17 is a recoil spring 85. The recoil spring 85 is constrained by a bracket 86 (partially shown) also supported by the supporting bracket 17. The purpose of recoil spring 85 is to prevent the needle bar 50, when latch surface 73 is disengaged from the bifurcated portion 58 of the driving stud 57, from being pulled to a height by the needle bar elevating spring 79 which would preclude relatching. To accomplish this objective, the recoil spring 85 bears on the elongated head portion 65 of screw 64 that secures the rectangular collar 62 to the needle bar 50. The vertical position of bracket 86 is adjusted so that the recoil spring 85 may hold the needle bar 50 against the bias of spring 79 at a position from which the needle bar may be relatched to the driving stud 57, as will be explained below.

Lateral Oscillation of the Needle Bar The upper rearwardly extending arm 36 of gate 35 has at the most rearward portion thereof a driving post 90 having a ball top 91 attached thereto (see FIG. 1). The ball top 91 fits into a socket 92 in an adjustable length link 93 extending across the sewing machine arm and terminating in a feeler 94 (see FIGS. 2 and 3). The feeler 94, under the influence of a biasing spring (not shown) acting on the adjustable length link 93, abuts a plate 95 pivoted on a pin 96 supported by the sewing machine frame. On the opposite side of the plate 95 from the feeler 94 is a cam follower 98, pivoting on a post 99 also supported by the sewing machine frame. The cam follower 98 impinges on the plate 95 and is forced, by the biasing spring acting on the feeler 94, against a basting stitch cam 100. The basting stitch cam 100 contains lobes 101 and valleys 102 of extended duration which correspond to skipped stitches. The valleys are deeper than those required for maximum right needle position while the lobes correspond to maximum left needle position. The lobes 101 force the cam follower 98, plate 95, feeler 94, and adjustable link 93 to the left, as viewed in FIGS. 2 and 3. By means of the connection of the adjustable link 93 to driving post 90 on the gate 35, the gate is caused to pivot counterclockwise, forcing the needle bar 50 to the left position.

The position of the various components are shown in FIGS. 7 and 10 the latter figure showing the gate 35 partially in section to show the latch mechanism at this needle position. The gate has attached, by screws 105, to the front thereof a latch release abutment member 106 which extends around the gate to the inside thereof adjacent the forwardly extending ear 72 of the latch lever 71.

The motion of the needle bar 50 and the abutment member 106 mounted on gate 35 will be better understood by initially referring to FIG. 1. The center line 52 indicates the path of reciprocation of the needle bar when the sewing machine is set for straight stitch center needle position corresponds to the axis of the bearings mounting the needle bar. The center line 1111 indicates the axis of oscillation of the gate 35. This line extends from the center of the outer spherical bearing surface 40 and socket bearing 42 to the center of the lower socket bearing 46 and the spherical head of the pivot stud 48. The center lines 52 and III intersect at the upper bearing 38 supporting both the gate 35 and the needle bar 50.

A motion induced by the lobe 101 on a cam 1100 will cause the gate 35 to rotate counterclockwise (see FIGS. 7 and III) and will cause the needle bar 50 and needle 51 to move to the left (FIG. 5), inasmuch as the lower internal bearing 47 of the needle bar is located inwardly from the axis of oscillation 1111 of the gate (see FIG. I).

Conversely, a motion induced by a valley of a cam of proportions to induce right needle position stitching, as shown in FIGS. b and II, will cause the gate 35 to rotate clockwise with a resulting motion of the needle 51 to the right.

In both cases the needle bar 50 and needle 51 move in the same direction as the driving post 9% affixed to the needle bar gate. More significantly, the abutment member 1106 attached to the gate 35 and the needle bar 51 carrying the latch mechanism 61 adjacent the abutment member move in opposite directions. It is this latter movement which is utilized to unlatch the latch surface 73 from the bifurcated portions 58 of the driving stud 57.

FIGS. 9 and 112 indicate the response to a Valley 102 in the basting stitch cam IIIII which valley is deeper than that required for maximum right needle position. The gate 35 and abutment member 1W6 attached thereto have rotated to a position clockwise of that in FIG. II or further to the left. The needle bar SII and the needle 51 have moved to a position to the right of that in FIG. 8. The abutment member 106 has rotated the latch lever 711 about the eccentric stud 69 by striking the forwardly extending ear 72, thereby causing the latch surface 73 to disengage from the bifurcated portions 58 of the driving stud 57. The needle bar 50 is held in an elevated position by the needle bar elevating spring 79 as constrained by the recoil spring 85 (see FIG. 6). While in this constrained position, the needle bar 50 is kept in the proper relatching alignment by protrusion of the extended head portion 65 of th screw 64 through a slot I in the pressure regulating system mounting plate 3%). In other positions of the needle bar SID the protrusion of the extended head portion I55 through the slot 115 assists the latch mechanism 611 in maintaining the sewing needle 51. in sewing position relative to the loop taker element in the sewing machine bed 112.

Thus, when the gate partakes of an extreme excursion to the left an abutment member 11% attached to the gate strikes a forwardly extending ear 72 of the latch lever 71, moving in the opposite direction or to the right and uncouples the latch lever from the needle bar reciprocating mechanism, thereby causing the needle bar to cease reciprocation (see FIGS. 6, 9 and I2). Removing the contact between the abutment member W6 and the forwardly extending ear 72 of the latch lever 7 I by rotating the gate to the right sufficiently will cause the latch lever 71 to rotate counterclockwise (FIG. 7) about the eccentric collar 69 under the influence of the torsion spring 75. When the bifurcated portion 58 of the driving stud 57 reaches the latch lever 71 held in the relatching position by the recoil spring 85, connection will again be made to the needle bar reciprocating mechanism of the sewing machine to reinitiate reciprocation of the needle bar (see FIGS. 5 and 6). The relatching of the bifurcated portion 58 of the driving stud 57 to the latch lever 7 I is aided by forming the bifurcated portion 5% with ramp surfaces II? and 11118 (see FIG. 4).

While the mechanism disclosed indicated a preferred embodiment of the invention, other mechanisms are possible which similarly would utilize any relative motion between a needle bar and a gate to trip a latch mechanism mounted on the needle bar by means of an abutment member mounted on the gate. The relative rotation of a needle bar with respect to the gate during lateral gogging is such a relative motion which could be utilized during an extreme lateral excursion of a simple gate having its axis of rotation parallel to the axis of reciprocation of the needle bar.

Having thus set forth the nature of this invention what I claim is:

I. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating mechanism carried in said sewing machine frame, means driven by said actuating mechanism for imparting endwise reciprocation to said needle bar through said latching means, and means for imparting lateral jogging motion to said gate; the improvement comprismg,

a. means for influencing relative motion between said gate and said needle bar during lateral jogging motion of said gate, and

b. abutment means carried by said gate and responsive to said motion relative to said needle bar during said lateral jogging to unIatch said latching means on said needle bar from said actuating means.

2. A skip stitch mechanism as claimed in claim I wherein said means for influencing relative motion between said gate and said needle bar includes an upper and a lower bearing, said upper bearing having a bearing surface supporting said gate in said sewing machine frame and having a coaxial internal bearing surface for said needle bar, said lower bearing having a bearing surface supporting said gate in said sewing machine frame spaced from an internal bearing surface for said needle bar in said gate.

3. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating I mechanism carried in said sewing machine frame,

b. abutment means carried by said gate and responsive to said motion relative to said needle bar during an extreme excursion of said lateral jogging to unlatch said latching means on said needle bar from said actuating means which imparts endwise reciprocation of said needle bar.

4. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating mechanism carried in said sewing machine frame, means driven by said actuating mechanism for imparting endwise reciprocation to said needle bar through said latching means and mechanism driven by said actuating mechanism for imparting lateral jogging motion to said gate and said needle bar; the improvement comprising:

a. a supporting bracket attachable to said sewing machine frame,

b. means mounting said gate in said supporting bracket for motion relative to said needle bar when driven by said actuating mechanism to impart lateral jogging motion to said needle bar, and

c. abutment means carried by said gate and responsive to said motion relative to said needle bar during an extreme excursion of said lateral jogging to unlatch said latch means on said needle bar from said actuating means which imparts endwise reciprocation to said needle bar.

5. A skip stitch mechanism as claimed in claim 4 wherein said means mounting said gate to said supporting bracket includes an upper and a lower bearing, said upper bearing having a bearing surface supporting said gate in said supporting bracket and having a coaxial internal bearing surface for said needle bar, said lower bearing having a bearing surface supporting said gate in said supporting bracket spaced from an internal bearing surface for said needle bar in said gate. 

1. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating mechanism carried in said sewing machine frame, means driven by said actuating mechanism for imparting endwise reciprocation to sAid needle bar through said latching means, and means for imparting lateral jogging motion to said gate; the improvement comprising, a. means for influencing relative motion between said gate and said needle bar during lateral jogging motion of said gate, and b. abutment means carried by said gate and responsive to said motion relative to said needle bar during said lateral jogging to unlatch said latching means on said needle bar from said actuating means.
 2. A skip stitch mechanism as claimed in claim 1 wherein said means for influencing relative motion between said gate and said needle bar includes an upper and a lower bearing, said upper bearing having a bearing surface supporting said gate in said sewing machine frame and having a coaxial internal bearing surface for said needle bar, said lower bearing having a bearing surface supporting said gate in said sewing machine frame spaced from an internal bearing surface for said needle bar in said gate.
 3. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating mechanism carried in said sewing machine frame, means driven by said actuating mechanism for imparting endwise reciprocation to said needle bar through said latching means and mechanism driven by said actuating mechanism for imparting lateral jogging motion to said gate and said needle bar; the improvement comprising: a. means for influencing relative motion between said gate and said needle bar when said gate is imparted lateral jogging motion by said acutating mechanism, and, b. abutment means carried by said gate and responsive to said motion relative to said needle bar during an extreme excursion of said lateral jogging to unlatch said latching means on said needle bar from said actuating means which imparts endwise reciprocation of said needle bar.
 4. A skip stitch mechanism in a sewing machine having a frame, an endwise reciprocating needle bar, a gate supporting said endwise reciprocating needle bar, latching means carried on said needle bar, actuating mechanism carried in said sewing machine frame, means driven by said actuating mechanism for imparting endwise reciprocation to said needle bar through said latching means and mechanism driven by said actuating mechanism for imparting lateral jogging motion to said gate and said needle bar; the improvement comprising: a. a supporting bracket attachable to said sewing machine frame, b. means mounting said gate in said supporting bracket for motion relative to said needle bar when driven by said actuating mechanism to impart lateral jogging motion to said needle bar, and c. abutment means carried by said gate and responsive to said motion relative to said needle bar during an extreme excursion of said lateral jogging to unlatch said latch means on said needle bar from said actuating means which imparts endwise reciprocation to said needle bar.
 5. A skip stitch mechanism as claimed in claim 4 wherein said means mounting said gate to said supporting bracket includes an upper and a lower bearing, said upper bearing having a bearing surface supporting said gate in said supporting bracket and having a coaxial internal bearing surface for said needle bar, said lower bearing having a bearing surface supporting said gate in said supporting bracket spaced from an internal bearing surface for said needle bar in said gate. 